不同浓度NaCl溶液下典型铝/钛合金电偶腐蚀当量折算关系

Equivalent conversion of galvanic corrosion of typical aluminum-titanium alloy in NaCl solution with different concentrations

通过电化学试验,分别测量了不同浓度NaCl溶液中2A12铝合金和TA15钛合金的极化曲线,利用极化曲线外推法,得到自腐蚀电流密度和自腐蚀电位,并分析其变化规律;测量了不同浓度、不同阴阳极面积比的电偶腐蚀电流;建立电偶腐蚀仿真模型,得到电偶电流仿真结果;基于仿真结果,利用当量折算系数法,计算不同浓度NaCl溶液与水介质的折算关系。结果表明:2种金属在溶液中存在电位差导致电偶腐蚀的发生;电偶电流的测试结果与仿真结果吻合较好,仿真模型可以用来对电偶腐蚀进行模拟;得到了2A12铝合金与TA15钛合金偶接后不同浓度NaCl溶液与水介质的折算系数。

Polarization curves of 2A12 aluminum alloy and TA]5 titanium alloy in NaCI solution of different concentration are measured by electrochemical tests separately. Self-corrosion current density and self-corrosion potential are obtained by the polarization curve extrapolation method, and change rules of them are analyzed. Galvanic corrosion current in different concentrations and different cathode/anode area ratios is measured. A galvanic corrosion simulation model is established, and simulation result of galvanic corrosion current is obtained. On the basis of the simulation results, equivalent relationships be- tween the NaCI solution of different concentration and the aqueous media are calculated through an equivalent conversion co- efficient method. Results indicate that galvanic corrosion occurs due to potential difference between two metals in a solution; Simulation results of galvanic current coincide well with electrochemical test results, and the simulation model can be used for simulating galvanic corrosion. Conversion coefficients of 2A12 aluminum alloy coupled with TA｜5 titanium alloy in the NaCI solution of different concentration and the aqueous media are obtained.